This invention relates in general to ovens and more particularly to an oven for maintaining foods at temperatures suitable for serving or for even cooking foods.
Most restaurants which specialize in serving cooked food rapidly--indeed, essentially with the placement of an order--do not have the capacity to prepare large quantities of food on demand. Thus, traditional meal times, particularly the noon hour, place severe demands on these restaurants. Typically, the so-called "fast food" restaurant will prepare some cooked food in advance of a meal time and keep that food warm in a holding oven. Then, during a meal time when the demand is greatest, it will use the food previously cooked.
Some cooked foods, such as hamburger patties, should be held at elevated temperatures only in a moist environment, since these foods, when depleted of their moisture content have poor taste and texture. Other cooked foods, such as breaded chicken or fish fillets, should be stored such that moisture may escape, so that they remain crisp. While it is convenient to store different foods at the same location, the flavor of one food should not transfer to another food. Moreover, irrespective of the food, the temperature at which it is stored must remain high enough to prevent bacterial contamination, and this generally requires holding the food at temperatures in excess of about 150.degree. F. Holding ovens that are currently in use in fast food restaurants do not fully satisfy these requirements.
The holding ovens of current manufacture accept trays containing the cooked foods. The typical oven has a cabinet containing storage spaces which are accessible from both the front and rear of the cabinet, so that a tray containing cooked food may be placed into a storage space at one face of the cabinet and withdrawn at the other face. Each storage space has a heated platen along its top and also preferably at its bottom, and these platens transfer heat to the trays. The cabinet also contains a mechanism for closing the upper ends of the trays to prevent moisture from escaping. In one type of holding oven this mechanism resides in making the spacing between a heated platen on which the tray rests and the heated platen which overlies the tray about equal to the height of the tray, so that the upper margin of the tray lies along and essentially against the overlying platen, thus in effect closing the tray. See U.S. Pat. No. 5,724,886. Another type of holding oven supports the tray on a resilient grate which urges a tray upwardly against an overlying heated platen, thereby effecting a seal with the overlying platen. See U.S. Pat. No. 5,783,803. These ovens are difficult to clean and do not efficiently concentrate the heat at the trays where it is needed. As a consequence, the food is often held at a temperature less than optimum. Sometimes, the spaces in these ovens hold trays with their tops open and this leads to a transfer of flavors between multiple trays in any one space. In any event, ovens of current manufacture have the capacity to store foods for only very limited periods of time.